Immobilization of Proteins into Microcapsules and Their Adsorption Properties with Respect to Precious-Metal Ions

Abstract

We report on protein immobilization in a microcapsule and its adsorption performance with respect to preciousmetal ions. Proteins including lysozyme, bovine serum albumin, chicken egg albumin, and soybean protein were immobilized by a microencapsulation method, and their adsorption properties with respect to ions of both precious metals (gold, platinum, and palladium) and base metals (zinc and copper) were investigated under various preparation conditions. Immobilized proteins could selectively adsorb precious-metal ions over base-metal ions. High immobilization efficiencies were obtained using lysozyme and soybean protein. The immobilization efficiency of the proteins was controlled by the surfactant concentration in the organic phase, the protein concentration, and the outer-aqueous-phase composition. We succeeded in immobilizing over 90% of the protein in the protein dose by optimizing the preparation conditions. Furthermore, the preciousmetal ions adsorbed by the immobilized proteins were completely recovered with thiourea. No leakage of proteins was observed after the adsorption and desorption experiments. These results indicate that the microcapsules immobilizing proteins prepared in the present study can be used as reusable precious-metalselective absorbents.

Recovery of gold(III) from an aqueous solution onto a durio zibethinus husk

“…Over the last two decades, adsorption has been considered to be a promising technology for the removal and/or recovery of metal ions with the advantages of high efficiency and simple operation [4]. Several biomasses have been used for adsorptive recovery of gold including tannin, fungal biomass, alfalfa, various protein sources and fruit wastes [5][6][7][8][9][10]. However, locally available and abundant low-cost adsorbent materials are still necessary in order to recover gold from particularly electronic and electroplating factories wastewater.…”

Immobilizing Enzymes on Noble Metal Hydrogel Nanozymes with Synergistically Enhanced Peroxidase Activity for Ultrasensitive Immunoassays by Cascade Signal Amplification

“…By taking advantage of the unique structures mentioned above, noble metal hydrogels hold great promise for loading enzymes. First, three-dimensional (3D) nanowire networks are beneficial to provide a high specific surface area and create a favorable microenvironment for loading enzymes. , The porous structure can also allow efficient mass transport and reduce diffusional resistance, enabling easier access to active sites of the enzymes by substrates. , Second, noble metals exhibit intrinsic affinity to proteins because noble metal ions can interact with surface functional groups on proteins. − This specific affinity also simplifies the procedures of enzyme immobilization without additional cross-linking agents. Finally, many noble metal nanomaterials and their alloy nanomaterials have shown promise as nanozymes and have been applied widely in the fields of biosensing and disease treatment. ,− Therefore, tuning noble metal hydrogel nanozymes is expected to efficiently immobilize enzymes and significantly boost their activity.…”

Selective recovery of gold(III) using cotton cellulose treated with concentrated sulfuric acid

“…In recent years, a variety of adsorbents prepared from biomass wastes and natural products including tannin, algae, fungi and yeast biomass, alfalfa, various protein sources and fruit wastes (Ogata and Nakano 2005;Gamez et al 2003;Kiyoyama et al 2008;Pethkar and Paknikar 1998;Karamuchka and Gadd 1999;Abidin et al 2011) have been tested for the recovery of gold. However, naturally abundant and low cost adsorption materials are still required to recover gold particularly from wastewater from electronic and electroplating factories and leach liquor of e-wastes.…”